title: Reliability of routine clearance methods for assessment of glomerular filtration rate in advanced renal insufficiency.
abstract: The reliability of different clearance methods to assess the glomerular filtration rate (GFR) was tested in fifteen patients with advanced chronic renal failure (range of GFR: 3-13 ml/min). The renal [51Cr]EDTA plasma clearance (Er) measured during optimal conditions with determination of residual bladder-urine was used as reference parameter of GFR and the reliability (+/-) of a thus corrected value to assess GFR of the individual patient are given in parenthesis. The arithmetic mean of the renal plasma clearance of endogenous creatinine (Clcreat) and urea (2.0 ml/min; +/- 1.5 ml/min); single determination of 25-h clcreat (3.4 ml/min; +/- 2.0 ml/min); Clcreat calculated from a measured plasma creatinine concentration, considering sex, age and body weight of the patient (2.9 ml/min; +/- 2.3 ml/min); total [51Cr]EDTA plasma clearance (Et) determined form three blood samples drawn 3-5 h after i.v. single injection 93.7 ml/min; +/- 2.2 ml/min); and Et determined form two blood samples drawn 4 and 24 h after i.v. injection (0.5 ml/min; +/- 0.5 ml/min). It is concluded that the most reliable assessment of GFR (=Er) is achieved either form a direct measurement or indirectly from Et determined from two blood samples drawn 5 and 24 h after i.v. single injection. use of the mean value of three 25-h Clcreat determinations is recommended if facilities for measurement of radioactivity are not available.
mesh_terms: D000328:Adult; D000368:Aged; D003404:Creatinine / Q000378:metabolism; D004492:Edetic Acid / Q000378:metabolism; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D014508:Urea / Q000378:metabolism
chemical_list: D014508:Urea; D004492:Edetic Acid; D003404:Creatinine